Influence of LRH on gonadotrophin and testosterone levels in the foetal male rat.
Gonadotrophin and testosterone levels were measured in male foetal rats at the 21st day of gestation 30 min following administration of LRH. The releasing hormone was administered by 3 different routes: subcutaneously as a single injection to the pregnant rat; subcutaneously as 12 times repeated injection to the pregnant rat from 16th-21st day of gestation; direct injection into the amniotic cavity. Three different doses of 1, 5, and 10 microgram/kg were used. The single administration to the dam was without effect. Repeated doses resulted in a significant dose-dependent elevation of mean foetal LH: 163 ng/ml in the control animals and 133,256, and 363 ng/ml in the 1, 5, and 10 microgram/kg LRH group resp. Intra animal injections significantly increased FSH and LH levels, but only those of FSH were clearly dose-dependent. A mean of 390 ng/ml in the control group was observed, with 1 microgram/kg LRH FSH was elevated to 723 ng/ml, at 5 microgram/kg to 928 and at 10 microgram/kg to 1017 ng/ml. Testosterone levels were not significantly altered. Our results demonstrate that the pituitary of foetal rats is able to respond to LRH in the same manner as adult animals.
D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D005333:Fetus; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011247:Pregnancy; D051381:Rats; D013739:Testosterone / Q000097:blood*
D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone